DevOps Lesson 7: Nginx

Nginx is the most popular web server. It serves static files, reverse proxies to Node/Python apps, handles SSL, and load balances. Essential for production.

Nginx as Reverse Proxy

# /etc/nginx/sites-available/myapp
server {
    listen 80;
    server_name myapp.com www.myapp.com;
    
    # Redirect HTTP to HTTPS
    return 301 https://$server_name$request_uri;
}

server {
    listen 443 ssl;
    server_name myapp.com;
    
    ssl_certificate /etc/letsencrypt/live/myapp.com/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/myapp.com/privkey.pem;
    
    location / {
        proxy_pass http://localhost:3000;  # forward to Node.js
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "upgrade";
        proxy_set_header Host $host;
        proxy_cache_bypass $http_upgrade;
    }
    
    location /api/ {
        proxy_pass http://localhost:4000;  # different backend!
    }
    
    # Serve static files directly (faster than Node.js)
    location /static/ {
        root /var/www/myapp;
        expires 30d;
    }
}

Free SSL with Let’s Encrypt

# Install certbot
sudo apt install certbot python3-certbot-nginx

# Get free SSL certificate
sudo certbot --nginx -d myapp.com -d www.myapp.com

# Renew automatically (certbot sets up cron)
sudo certbot renew --dry-run